A patient with severe abdominal pain had a stool culture revealing non-lactose-fermenting, Gram-negative rods that produce gas in nutrient broth. What is the most likely causative agent?

Correct Answer: D

Rationale: The correct answer is D: Proteus vulgaris. This is because Proteus species are non-lactose-fermenting, Gram-negative rods that produce gas in nutrient broth. They are known to cause severe abdominal pain due to their ability to invade the intestinal mucosa. A: Salmonella enterica is a lactose-fermenting organism and typically does not produce gas in nutrient broth. B: Shigella dysenteriae is a lactose-negative organism but does not produce gas in nutrient broth. C: Escherichia coli is a lactose-fermenting organism and does not typically produce gas in nutrient broth. In summary, the presence of non-lactose-fermenting, gas-producing Gram-negative rods points towards Proteus vulgaris as the most likely causative agent of the severe abdominal pain.

Correct Answer: D

Rationale: The correct answer is D: Primaquine. Primaquine is used for individual chemoprophylaxis of malaria caused by Plasmodium vivax and Plasmodium ovale. It is effective in preventing the relapse of these malaria species by eliminating the liver forms of the parasites. Chingamin (A) is not a commonly used drug for malaria prophylaxis. Pyrantel (B) is an anthelmintic drug used for treating parasitic worm infections, not malaria. Pyrimethamine (Chloridinum) (C) is primarily used in combination with sulfadoxine for treating uncomplicated malaria, not for chemoprophylaxis.

Correct Answer: C

Rationale: 1. OSHA stands for Occupational Safety and Health Administration. 2. OSHA is responsible for ensuring safe and healthy working conditions in the US. 3. The U.S. Department of Labor oversees OSHA's operations and regulations. 4. Therefore, the correct answer is C, as OSHA is a division of the U.S. Department of Labor. 5. Other choices are incorrect because they are not directly related to OSHA's jurisdiction or responsibilities.

Correct Answer: C

Rationale: The correct answer is C: urethra. Resident microflora refers to the normal, beneficial bacteria that inhabit a specific area of the body without causing harm. The urethra is one of the locations where resident microflora are commonly found. These bacteria play a vital role in maintaining a healthy balance and preventing harmful pathogens from colonizing the urethra. Blood (A), lung (B), and cerebro-spinal fluid (D) are not typical locations for resident microflora as these areas are usually sterile or have very limited microbial presence to prevent infections.

Correct Answer: B

Rationale: The correct answer is B: Corynebacterium diphtheriae. This bacterium produces a toxin that causes diphtheria. It forms a grayish membrane in the throat, leading to difficulty breathing. Bacillus anthracis (Choice A) causes anthrax, Streptococcus pneumoniae (Choice C) causes pneumonia, and Escherichia coli (Choice D) causes various infections but not diphtheria.

Correct Answer: B

Rationale: Rationale: 1. Streptococcus pyogenes is the causative agent of strep throat. 2. If untreated, strep throat can lead to rheumatic fever. 3. Rheumatic fever is an autoimmune complication of streptococcal infections. 4. E. coli, S. epidermidis, and S. aureus are not typically associated with rheumatic fever.

Correct Answer: D

Rationale: The correct answer is D, "All of the above." Bacterial meningitis can be caused by Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae. These bacteria are common pathogens associated with meningitis. Each of them can lead to serious infections in the brain and spinal cord. Neisseria meningitidis is known for causing meningococcal meningitis, Haemophilus influenzae is a common cause of H. influenzae meningitis, and Streptococcus pneumoniae is responsible for pneumococcal meningitis. Therefore, since all three bacteria can cause bacterial meningitis, the correct answer is D. Choices A, B, and C are incorrect because each of these bacteria individually can cause bacterial meningitis; it is not limited to just one specific type.

Correct Answer: C

Rationale: Rationale: 1. Psychrophilic: Grow best in cold temperatures 2. Mesophilic: Grow best in moderate temperatures 3. Thermophilic: Grow best in high temperatures - Choice A is incorrect as "thermophobic" is not a recognized term. - Choice B is incorrect as "psychophobic" is not a recognized term. - Choice D is incorrect as "mesophobic" is not a recognized term.

Correct Answer: B

Rationale: The correct answer is B: cell wall. Lysozyme is an enzyme that targets the cell wall of bacteria by breaking down the peptidoglycan layer, leading to bacterial cell lysis. This action disrupts the structural integrity of the bacteria, ultimately causing their death. Choices A, C, and D are incorrect because lysozyme does not target the cytoplasm, nucleus, or capsule of bacteria. The primary function of lysozyme is to act on the cell wall, making option B the correct answer in this context.